1. Field of the Invention
The present invention relates to a cold cathode device which can perform various functions such as amplification by controlling the flow of electrons emitted from a cold cathode.
2. Related Background Art
Semiconductor devices such as diodes and transistors constructed of p-type and n-type semiconductor regions are widely used as circuit elements performing rectification or amplification.
Semiconductor devices have many advantages: small size, light weight, feasibility of integration, large cost reduction, long life, high reliability and so on. Semiconductor devices are used accordingly in various applications such as information machines including computers, electronic household appliances including television, radio and the like.
Semiconductor devices such as diodes and transistors have some problems, including that malfunctioning may occur due to radiation of alpha-rays or the like. Semiconductor devices cannot be used in the range of GHz due to a limit of response speed which is in the order of up to 100 MHz in case of Si transistors.
A vacuum tube may be used to realize a high speed response. However, a hot cathode is generally used in a tube to emit electrons from the surface of a metal by heating it to high temperature in vacuum. One of the disadvantages of tubes is therefore a warm-up time required for such heating. Further, A tube of this kind includes therein a cathode, grid, plate and other electrodes so that it is difficult to make it compact. Because of heat radiation, a tube cannot be integrated with semiconductor devices.